Method for the preparation of chlorinated anthraquinones



Patented June 3, 1930 UNITED STATES PATENT; OFFICE JOSEPH DEINET, OIMILWAUKEE, WISCONSIN, ASSIGNOR TO THE NEWPORT COMPANY, OF CARROLLVILLE,WISCONSIN, A CORPORATION OF DELAWARE METHOD FOR THE PREPARATION OFCHLORINATEZD ANTHRAQUINONES No Drawing.

This invention relates to a method for the preparation of chlorinatedanthraquinones, as for instance, 1,5-dichloro anthraquinone,1,8-dichloro anthra uinone, l-nitro -chloro 5 anthraquinone, 2-ch o'roanthraquinone, and

the like. r

It is an object of this invention to provide an improved, economical andpractical method for the preparation of chlorinated g anthraquinones bythe replacement of the sulfonic acid group in an anthraquinone body withchlorine. I am aware that methods have been previously described for thepreparation of these products. The resent process,

however, possesses many a vantages over previously disclosed methods asregards economy of raw materials and in the simplicity of the apparatusnecessary for technical manufacture.

invention will be apparent from the disclosures in the specification andthe appended claims.

Hitherto known methods, in eneral, em-

ploy as starting material, the Isolated sulfonic acid salts. Further, asa reaction medium these methods em loy hydrochloric acid and the generalproce ure consists inmtroducing either chlorine as such, or sodium ch10ate, into the solution of the respective sul nic acid in thehydrochloric acid.

In the present invention, there is described a method whereby sulfuricacid is used as the reaction medium. By my process, it is not necessaryto employ an isolated sulfonic acid salt as starting material, for thereaction medium employed may be the dilutedsulfonation mass itself.However, it is understood 40 that isolated sulfonic acids may employed,

if desired, with sulfuric acid as the reaction medium. The generalprocess comprises dissolving or suspending the sulphonic acid in dilutedsulfuric acid, heating this mixture to the boiling point and slowlyintroducing a mixture of sodium chloride and sodium chlorate at theelevated temperature. ture of sodium chloride and sodium chlorate ispreferably added in the form of a solution in order to regulate moreclosely the libera- Other and further important objects of this The mix-Application filed December 19, 1927. SerlaI No. 241,273.

tion of chlorine for chlorinating the anthraquinone sulphonic acids.

It was not obvious that sulfuric acid could be employed in making theseproducts. In 3013 113 has been stated in the literature by an eminentauthority that the reaction does not proceed under these conditions.This method not only possesses the advantage as described above, wherebyan isolated sulphomc acid may be dispensed with, but allowslessexpensive apparatus to be used in the commercial production of theseproducts, since the use of sulphuric acid permits lead lined apparatusto be utilized.

Without limitingmy invention to any partlcular procedure, the followingexamples, in which 'parts by weight are expressed, illustrateembodiments of my preferred method:

Emample I Emample H 10 parts of 1,5-nitro anthraquinone sulfonic acidare charged into 400 parts of water and 30 parts of concentrated (about93%) sulfuric acid added to it. The mass is brought to boiling and thena solution of 10 parts of sodium chloride and 10 parts of sodiumchlorate in 60 parts of water is slowly run in over a period of 10 to 12hours. The resulting l-nitro 5-chloro anthraquinone is filtered andwashed acid free. The yield is close to the theoretical.

Ewample II 10 parts of anthraquinone are su-lfonated in beta position,the mass then poured into 400 10? parts of water, the whole mass boiledup and filtered from unchanged anthraquinone. Into the filtrate togetherwith the wash Water, 5 parts of sodium chloride with 5 parts of sodiumchlorate in 30 parts of Water are slowly charged, the whole being at theboiling point. The resulting .Z-chloro anthraquinone is filtered andwashed acid free. The yield is close to that theoretically expected.

I am aware of the fact that chlorinating agents other than sodiumchloride-sodium chlorate mixture may be used. In general, such reagentsmay be used as are adapted for the preparation of nascent chlorine. Tobe suitable halogenating agents, the oxidizing agent used for generatingthe nascent chlorine must be of such a nature that any excess used willnot react to decompose the organic molecule.

I am aware that numerous details of the process may be varied through awide range without departing from the principles of this invention, andI, therefore, do not purpose limiting the patent granted hereonotherwise than necessitated by the prior art.

I claim as my invention:

1. The process of preparing chloro-anthraquinones, which comprisestreating a boiling solution of anthraquinone sulphonic acids in dilutesulphuric acid with sodium chloride and sodium chlorate.

2. The process of preparing 1,8-dichloro anthraquinone, which comprisesheating a solution of 1,8-anthraquinone disulphonic acid in dilutesulphuric acid to the boiling point, adding sodium chloride and sodiumchlorate simultaneously to said solution over a prolonged period of timeand filtering 011' the resulting insoluble 1,8-dichloroanthraquinone.

8. The process of preparing chloro-anthraquinones, which comprisestreating a solution of anthraquinone sulphonic acids 1n dilute sulphuricacid at around boiling temperatures with an alkali metal chloride andchlorate, said chloride and chlorate being slowly introduced in the formof a solution of the salts.

I. In the process of preparing chloro-anthraquinones, the step whichcomprises adding slowly to a boiling solution of an anthraquinonesulphonic acid in dilute sulphuric acid, a solution of an alkali metalchloride and chlorate.

5. In the process of preparing chloro-anthraquinones, the step whichcomprises adding slowly to a boiling solution of an antl1ra-- quinonesulphonic acid in dilute sulphuric acid, a solution of sodium chlorideand sodium chlorate mixed in substantially equal proportions.

In testimony whereof I have hereunto subscribed my name.

JOSEPH DEINET.

